This invention relates to a vehicle disc brake device of the kind in which friction pads are adapted to be urged by hydraulic acting means into engagement with opposite faces of a friction disc and the hydraulic acting means being a sliding fit on a stationary part of a vehicle wheel and straddling a periphery portion of the brake disc together with the pads.
In the known device of this kind, the hydraulic fluid acting means is slidably supported on a pair of parallel guiding pins projecting from the stationary part of the vehicle wheel. For safety braking purpose, an early or prompt response to the varying brake operating fluid pressure is required for the brake device. To meet such requirement, the fluid acting means must normally be kept in a sufficiently sliding fit condition on the guiding pins. In order to hold the hydraulic acting means in sufficiently sliding fit condition on the pins, severe accuracy of parallel relationship is required between the two pins when installed. The same accuracy is also required between a pair of corresponding engagement portions in the fluid acting means, with the space therebetween strictly in accord with that of the pins. This requirement is apt to impose a heavy burden upon manufacturing the device and considered therefore to be a disadvantage in saving the substantial manufacturing costs.
In has heretofore been known in the art that deformable resilient means such as rubber member may be adapted to be inserted between the hydraulic acting means and the pins in order that installation or manufacturing of the parts may be considerably tolerated. However, such spacer means has never proven to be sufficient by reason of the fact that an amount of deformation as would sufficiently allow a desired degree of such tolerance otherwise exhibits a tendency to cause an objection to holding the hydraulic acting means normally in best sliding condition on the pins.